Display device and method for manufacturing the same, and television receiver

ABSTRACT

According to the present invention, which is a display device in which a light-emitting element where an organic substance generating luminescence referred to as electroluminescence or a medium including a mixture of an organic substance and an inorganic substance is sandwiched between electrodes is connected to a TFT, the invention is to manufacture a display panel by forming at least one or more of a conductive layer which forms a wiring or an electrode and a pattern necessary for manufacturing a display panel such as a mask layer for forming a predetermined pattern is formed by a method capable of selectively forming a pattern. A droplet discharge method capable of forming a predetermined pattern by selectively discharging a droplet of a composition in accordance with a particular object and by forming a conductive layer or an insulating layer is used as a method capable of selectively forming a pattern.

TECHNICAL FIELD

The present invention relates to a display device to which an activeelement such as a transistor formed over a glass substrate is appliedand to a method for manufacturing the same.

BACKGROUND ART

Conventionally, a display panel of a so-called active matrix drivingmethod constituted by a thin film transistor (hereinafter also referredto as a “TFT”) over a glass substrate is known. As well as amanufacturing technique of a semiconductor integrated circuit, thisdisplay panel needs a step of patterning a thin film such as aconductor, a semiconductor, or an insulator due to a light-exposure stepusing a photomask.

A size of a mother glass substrate used for manufacturing a displaypanel is enlarged from 300 mm×400 mm of the first generation in theearly 1990s to 680 mm×880 mm or 730 mm×920 mm of the fourth generationin 2000. Furthermore, the manufacturing technique made such adevelopment that a number of display panels can be obtained from onesubstrate.

When a size of a glass substrate or a display panel is small, patterningtreatment can be carried out comparatively easily by using aphotolithography machine. However, as a substrate size is enlarged, anentire surface of a display panel cannot be simultaneously treated bycarrying out light-exposure treatment once. Consequently, it isnecessary to divide a region where a photoresist is applied into aplurality of block regions and to carry out light-exposure treatment onevery predetermined block regions. As for light-exposure treatment, amethod for exposing an entire surface of a substrate to light bysequentially repeating the treatment has been developed (for example,see Reference 1: Japanese Patent Application Laid-Open No. Hei 11-326951and Reference 2: U.S. Pat. No. 6,291,136).

DISCLOSURE OF INVENTION

However, a glass substrate is further enlarged to a size of 1000 mm×1200mm or 1100 mm×1300 mm in the fifth generation, and a size of 1500mm×1800 mm or more is assumed in the next generation. A large sizedglass substrate is effective in enlarging an area and increasing thenumber of a display panel to be obtained; however, it is difficult tomanufacture a display panel at good productivity by low cost in aconventional patterning method. In other words, when a plurality oftimes of light-exposure is carried out by consecutive light exposure, aprocessing time is increased and tremendous investment is required fordeveloping a photolithography machine that can treat a large-sized glasssubstrate.

Moreover, in a method for forming various types of thin films over anentire surface of a substrate and for removing the thin films to leave aslight region by etching, there is a problem that a material cost iswasted and disposal of a large quantity of effluent is forced.

In view of the above situation, the object of the present invention isto provide a display device capable of improving utilizing efficiency ofa material and of simplifying a manufacturing step and a manufacturingtechnique thereof.

Means to Solve the Problem

According to one aspect of the present invention, at least one or moreof a conductive layer which forms a wiring or an electrode and a patternnecessary for manufacturing a display panel such as a mask for forming apredetermined pattern is formed by a method capable of selectivelyforming a pattern to manufacture a display panel. A droplet dischargemethod (also referred to as a ink-jet method by the system to beapplied) capable of forming a predetermined pattern by selectivelydischarging a droplet of a composition in accordance with a particularobject is used as a method capable of selectively forming a pattern.

In the invention, the above-mentioned object is achieved by completing adisplay device, by using a droplet discharge method, in which a TFT isconnected to a light-emitting element where an organic materialgenerating luminescence referred to as electroluminescence (hereinafteralso referred to as “EL”) or a medium including a mixture of an organicmaterial and an inorganic material is sandwiched between electrodes.

According to another aspect of the invention, a method for manufacturinga light-emitting device comprises the steps of: forming a gate electrodeover a substrate having an insulating surface with a droplet dischargemethod; laminating a gate insulating layer, a semiconductor layer, andan insulating layer over the gate electrode; forming a first mask in aposition overlapping with the gate electrode with a droplet dischargemethod; forming a channel protective layer by etching the insulatinglayer by the first mask; forming a semiconductor layer containing oneconductivity type impurity; forming a second mask in a region includingthe gate electrode with a droplet discharge method; etching thesemiconductor layer containing one conductivity type impurity and thesemiconductor layer under the semiconductor layer containing oneconductivity type impurity; forming wirings to be connected to a sourceand a drain with a droplet discharge method; and, etching thesemiconductor layer containing one conductivity type impurity on thechannel protective layer by using the wirings to be connected to thesource and the drain as masks.

According to another aspect of the invention, a method for manufacturinga light-emitting device comprises the steps of: forming a gate electrodeand a connection wiring over a substrate having an insulating surfacewith a droplet discharge method; laminating a gate insulating layer, asemiconductor layer, and an insulating layer over the gate electrode;forming a first mask in a position overlapping with the gate electrodewith a droplet discharge method; forming a channel protective layer byetching the insulating layer by the first mask; forming a semiconductorlayer containing one conductivity type impurity; forming a second maskin a region including the gate electrode with a droplet dischargemethod; etching the semiconductor layer containing one conductivity typeimpurity and the semiconductor layer under the semiconductor layercontaining one conductivity type impurity; partially exposing theconnection wiring by selectively etching the gate insulating layer;forming wirings to be connected to a source and a drain with a dropletdischarge method and connecting at least one of the wirings to theconnection wiring, and etching the semiconductor layer containing oneconductivity type impurity on the channel protective layer by using thewirings to be connected to the source and the drain as masks.

In the above-mentioned step of laminating a gate insulating layer, asemiconductor layer, and an insulating layer over the gate electrode, itis preferable to successively form each layer of the gate insulatinglayer, the semiconductor layer, and the insulating layer withoutexposing to the atmosphere by a vapor phase growth method using plasma(plasma CVD) or a sputtering method.

By sequentially laminating a first silicon nitride film, a silicon oxidefilm, and a second silicon nitride film to form a gate insulating film,the gate electrode can be prevented from being oxidized and asatisfactory interface between the gate insulating film and thesemiconductor layer formed over the upper layer side of the gateinsulating film can be formed.

As mentioned above, according to the other aspect of the invention, thegate electrode, the wiring, and the mask used during patterning areformed by a droplet discharge method. However, at least one or more ofpatterns necessary for manufacturing an EL display device is formed by amethod capable of selectively forming a pattern to manufacture a displaydevice, thereby achieving the object.

According to the following aspect of the invention, a display device hasa pixel portion arranging in a matrix a light-emitting element where anorganic material including a light-emitting material generating EL or amedium including a mixture of an organic material and an inorganicmaterial is sandwiched between a pair of electrodes, and capable ofcontrolling a luminescent state and non-luminescent state by connectingeach light-emitting element to a TFT.

According to the other aspect of the invention, a light-emitting devicecomprises: a light-emitting element in which a light-emitting materialis sandwiched between a pair of electrodes; and a thin film transistorincluding from a substrate side a lamination of: a gate electrode formedby making fusion and/or welding (by fusing) of conductive nanoparticles;a gate insulating layer at least containing a silicon nitride layer or asilicon nitride oxide layer formed to be in contact with the gateelectrode, and a silicon oxide layer; and a semiconductor layer, whereina pixel in which the light-emitting element and the thin film transistorare connected is provided.

According to the other aspect of the invention, a light-emitting devicecomprises: a light-emitting element in which a light-emitting materialis sandwiched between a pair of electrodes; and a thin film transistorincluding from a substrate side a lamination of: a gate electrode formedby making fusion and/or welding (by fusing) of conductive nanoparticles;a gate insulating layer at least containing a silicon nitride layer or asilicon nitride oxide layer formed to be in contact with the gateelectrode, and a silicon oxide layer, a semiconductor layer, wiringsconnected to a source and a drain and formed by making fusion and/orwelding (by fusing) of conductive nanoparticles; and a silicon nitridelayer or silicon nitride oxide layer formed to be in contact with thewirings, wherein a pixel in which the light-emitting element and thethin film transistor are connected is provided.

According to the other aspect of the invention, a light-emitting devicecomprises: a light-emitting element in which a light-emitting materialis sandwiched between a pair of electrodes; and a first thin filmtransistor including from a substrate side a lamination of: a gateelectrode formed by making fusion and/or welding (by fusing) ofconductive nanoparticles; a gate insulating layer at least containing asilicon nitride layer or a silicon nitride oxide layer formed to be incontact with the gate electrode, and a silicon oxide layer; and asemiconductor layer; a driver circuit including a second thin filmtransistor formed by having the same layer structure as that of thefirst thin film transistor; and a wiring extended from the drivercircuit and connecting to the gate electrode of the first thin filmtransistor, wherein the light-emitting element and a pixel connected tothe first thin film transistor are provided.

According to other aspect of the invention, a light-emitting devicecomprises: a light-emitting element in which a light-emitting materialis sandwiched between a pair of electrodes; and a first thin filmtransistor including, from a substrate side, a lamination of: a gateelectrode formed by making fusion and/or welding (by fusing) ofconductive nanoparticles; a gate insulating layer at least containing asilicon nitride layer or a silicon nitride oxide layer formed to be incontact with the gate electrode, and a silicon oxide layer; asemiconductor layer; wirings connected to a source and a drain andformed by making fusion and/or welding (by fusing) of conductivenanoparticles; and a silicon nitride layer or silicon nitride oxidelayer formed to be in contact with the wirings; a driver circuitincluding a second thin film transistor formed by having the same layerstructure as that of the first thin film transistor; and a wiringextended from the driver circuit and connecting to the gate electrode ofthe first thin film transistor, wherein the light-emitting element and apixel connected to the first thin film transistor are provided.

According to the invention, the gate electrode or the wiring is formedwith a droplet discharge method, and a conductive material can be formedof Ag or an alloy containing Ag. In addition, a silicon nitride film ora silicon nitride oxide film is provided over the gate electrode or anupper layer of the wiring by being in contact; therefore, the gateelectrode can be prevented from being deteriorated due to oxidization.

In the invention, it is also possible that the semiconductor layer,which is a main portion of a TFT, contains hydrogen and halogen, and isformed from a semi-amorphous semiconductor containing a crystalstructure. Accordingly, a driver circuit only including an n-channeltype TFT can be provided. In other words, the semiconductor layercontains hydrogen and halogen and is a semiconductor having a crystalstructure, thereby realizing the driver circuit over one substrate bythe TFT which is capable of being operated with electric field effectmobility of from 1 cm²/V·sec to 15 cm²/V·sec cm².

According to the present invention, patterning of a wiring or a mask canbe carried out directly by a droplet discharge method; therefore, a TFTin which utilization efficiency of a material is improved and amanufacturing step is simplified, and a display device using the TFT canbe obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a top view illustrating a structure of an EL display panelaccording to a certain aspect of the present invention;

FIG. 2 shows a top view illustrating a structure of an EL display panelaccording to a certain aspect of the invention;

FIG. 3 shows a top view illustrating a structure of an EL display panelaccording to a certain aspect of the invention;

FIGS. 4A to 4C each show cross-sectional views illustrating a step ofmanufacturing an EL display panel according to certain aspects of theinvention;

FIGS. 5A to 5C each show cross-sectional views illustrating a step ofmanufacturing an EL display panel according to certain aspects of theinvention;

FIGS. 6A to 6C each show cross-sectional views illustrating a step ofmanufacturing an EL display panel according to certain aspects of theinvention;

FIG. 7 shows a cross-sectional view illustrating a step of manufacturingan EL display panel according to a certain aspect of the invention;

FIG. 8 shows a top view illustrating a step of manufacturing an ELdisplay panel according to a certain aspect of the invention;

FIG. 9 shows a top view illustrating a step of manufacturing ad ELdisplay panel according to a certain aspect of the invention;

FIG. 10 shows a top view illustrating a step of manufacturing an ELdisplay panel according to a certain aspect of the invention;

FIG. 11 shows a top view illustrating a step of manufacturing an ELdisplay panel according to a certain aspect of the invention;

FIGS. 12A to 12C each show cross-sectional views illustrating a step ofmanufacturing an EL display panel according to certain aspects of theinvention;

FIG. 13 shows a cross-sectional view illustrating a step ofmanufacturing an EL display panel according to a certain aspect of theinvention;

FIG. 14 shows a cross-sectional view illustrating a step ofmanufacturing an EL display panel according to a certain aspect of theinvention;

FIG. 15 shows a top view illustrating an EL display panel according to acertain aspect of the invention;

FIG. 16 shows an equivalent circuit diagram of an EL display panelillustrated in FIG. 15;

FIGS. 17A and 17B each show diagrams illustrating modes of an applicablelight-emitting element according to certain aspects of the invention;

FIGS. 18A and 18B each show diagrams illustrating modes of an applicablelight-emitting element according to certain aspects of the invention;

FIGS. 19A and 19B each show a mounting method of a driver circuit of anEL display panel according to certain aspects of the invention;

FIGS. 20A and 20B each show a mounting method of a driver circuit of anEL display panel according to certain aspects of the invention;

FIGS. 21A to 21F each show circuit diagrams illustrating a structure ofa pixel applicable to an EL display panel according to certain aspectsof the invention;

FIG. 22 shows a diagram illustrating a circuit structure in the case offorming a scanning line driver circuit with a TFT in an EL display panelaccording to a certain aspect of the invention;

FIG. 23 shows a diagram illustrating a circuit structure in the case offorming a scanning line driver circuit with a TFT in an EL display panelaccording to a certain aspect of the invention (a shift registercircuit);

FIG. 24 shows a diagram illustrating a circuit structure in the case offorming a scanning line driver circuit with a TFT in an EL display panelaccording to a certain aspect of the invention (a buffer circuit);

FIG. 25 shows a view illustrating a structure of a droplet dischargedevice applicable to a certain aspect of the invention;

FIG. 26 shows a cross-sectional view illustrating an EL display panelaccording to a certain aspect of the invention;

FIG. 27 shows a cross-sectional view illustrating a structure example ofan EL display module according to a certain aspect of the invention;

FIG. 28 shows a cross-sectional view describing a structure example ofan EL display module according to a certain aspect of the invention;

FIG. 29 shows a block diagram of a main structure of an EL televisionreceiver according to a certain aspect of the invention;

FIG. 30 shows a view illustrating a structure of an EL televisionreceiver to be completed according to a certain aspect of the invention;and

FIG. 31 shows a top view illustrating an EL display panel according to acertain aspect of the invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment mode of the present invention will be explained in detailwith reference to the drawings. Note that the same reference numeralsdenote the same parts among each drawing, and the explanation will notbe repeated in the following explanations. In addition, it is to beunderstood that various changes and modifications will be apparent tothose skilled in the art, unless such changes and modifications departfrom content and the scope of the invention. Therefore, the invention isnot interpreted with limiting to the description in this embodimentmode.

FIG. 1 shows a top view of a structure of an EL display panel accordingto the present invention. A pixel portion 101 in which pixels 102 arearranged in a matrix, a scanning line input terminal 103, and a signalline input terminal 104 are formed on a substrate 100 having aninsulating surface. The number of pixels may be provided according tovarious standards. The number of pixels of XGA may be 1024×768×3 (RGB),that of UXGA may be 1600×1200×3 (RGB), and that of a full-speck highvision to correspond thereto may be 1920×1080×3 (RGB).

The pixels 102 are arranged in a matrix by intersecting a scanning lineextended from the scanning line input terminal 103 with a signal lineextended from the signal line input terminal 104. Each pixel 102 isprovided with a transistor for controlling a connection state betweenthe signal line and a driving transistor (hereinafter, also referred toas a “switching transistor” or a “switching TFT”) and a transistor forcontrolling current flowed through a light-emitting element(hereinafter, also referred to as a “driving transistor” or a “drivingTFT”), and the driving transistor is connected in series to thelight-emitting element.

A TFT includes a semiconductor layer, a gate insulating layer, and agate electrode as main components. A wiring connected to a source anddrain regions formed in the semiconductor layer is included too. A topgate type in which a semiconductor layer, a gate insulating layer, and agate electrode are arranged from the substrate side, a bottom gate typein which a gate electrode, a gate insulating layer, and a semiconductorlayer are arranged from the substrate side, or the like is known as astructure of a TFT. However, any one of structures may be applied to theinvention.

An amorphous semiconductor (hereinafter also refereed to as an “AS”)manufactured by using a semiconductor material gas typified by silane orgermane with a vapor phase growth method or a sputtering method; apolycrystalline semiconductor that is formed by crystallizing theamorphous semiconductor by utilizing light energy or thermal energy; asemi-amorphous (also referred to as microcrystallite ormicrocrystalline, and hereinafter also referred to as an “SAS”)semiconductor; or the like can be used for a material which forms asemiconductor layer.

An SAS is a semiconductor with an intermediate structure between anamorphous and a crystal structure (including a single crystal and apolycrystal). This is a semiconductor having a third condition that isstable as a case of a free energy, and a crystalline region having ashort distance order and lattice distortion is included therein. Acrystalline region of from 0.5 nm to 20 nm can be observed at least in apart of region in the film. When silicon is contained as the maincomponent, Raman spectrum is shifted to a lower frequency side less than520 cm⁻¹. Diffraction peak of (111) or (220) to be caused from a crystallattice of silicon is observed in X-ray diffraction. At least 1 atomic %or more of hydrogen or halogen is contained to terminate a danglingbond. An SAS is formed by carrying out grow discharge decomposition(plasma CVD) on a silicide gas. In addition to SiH₄, Si₂H, SiH₂Cl₂,SiHCl₃, SiCl₄, SiF₄, or the like can be used for the silicide gas. Inaddition, GeF₄ may be mixed. This silicide gas may be diluted with H₂ orH₂ and one or more of the rare gas element of He, Ar, Kr, and Ne. Adilution ratio ranges from 2 times to 1000 times. A pressure rangesapproximately from 0.1 Pa to 133 Pa, and a power frequency ranges from 1MHz to 120 MHz, preferably from 13 MHz to 60 MHz. A substrate heatingtemperature may be 300° C. or less. It is desirable that an atmosphericconstituent impurity such as oxygen, nitrogen, or carbon is 1×10²⁰ cm⁻¹or less as an impurity element in the film, specifically an oxygenconcentration is 5×10¹⁹/cm³ or less, preferably 1×10¹⁹/cm³ or less.

FIG. 1 shows a structure of an EL display panel that controls a signalinputting into a scanning line and a signal line by an external drivercircuit. Furthermore, a driver IC may be mounted on a substrate 100 by aCOG (Chip on Glass) as shown in FIG. 2. FIG. 2 shows a mode in which ascanning line driver IC 105 and a signal line driver IC 106 are mountedon the substrate 100. The scanning line driver IC 105 is providedbetween a scanning line input terminal 103 and a pixel portion 101.

In addition, a TFT provided for a pixel can be formed from an SAS. Sincea TFT using an SAS has an electric field effect mobility of from 1cm²/V·sec to 15 cm²/V·sec, a driver circuit can be formed. FIG. 3 showsan example of forming a scanning line driver circuit 107. Furthermore, aprotective circuit 108 can be also provided between the scanning linedriver circuit 107 and a pixel portion 101. The number of inputterminals can be reduced by forming the scanning line driver circuit 107from a TFT on the substrate 100.

FIG. 25 shows one mode of a droplet discharge device used for formingpatterns. Each head 1403 of a droplet discharge means 1401 isindividually connected to a control means 1404. The control means 1404controls droplet discharge from the head 1403. The timing of dischargingdroplet is controlled based on the program inputted into a computer1407. A position of discharging a droplet may be decided based on amarker 1408 formed on a substrate 100 for example. In addition, areference point may be fixed with an edge of the substrate 100 as areference. A reference point is detected by an imaging means 1402 suchas a CCD, and the computer 1407 recognizes a digital signal converted byan image processing means 1406 to generate a control signal. Of course,information of a pattern to be formed on the substrate 100 is placed ina recording medium 1405. Based on this information, the control signalcan be transmitted to the control means 1404 and each head 1403 of thedroplet discharge means 1401 can be controlled individually.

Next, a step of manufacturing an EL display panel using such a dropletdischarge device is explained hereinafter.

Embodiment Mode 1

A method for manufacturing a channel protective type TFT and a displaydevice with the use thereof are explained in Embodiment mode 1.

FIG. 4A shows a step of forming a gate electrode, and a gate wiring anda capacitor wiring connected to the gate electrode over a substrate 100with a droplet discharge method. Note that FIG. 4A shows a longitudinalsectional structure, and FIG. 8 shows a planar structure correspondingto A-B and C-D thereof.

In addition to a non-alkaline glass substrate such as bariumborosilicate glass, alumino borosilicate glass, or aluminosilicate glassmanufactured with a fusion method or a floating method, and a ceramicsubstrate, a plastic substrate having the heat resistance that canwithstand processing temperature or the like can be used for thesubstrate 100. In addition, a semiconductor substrate such as singlecrystal silicon, a substrate in which a surface of a metal substratesuch as stainless is provided with an insulating layer may be appliedtoo.

A base layer 201 formed from a metal material such as Ti (titanium), W(tungsten), Cr (chromium), Ta (tantalum), Ni (nickel), or Mo(molybdenum) or an oxide thereof is preferably formed on the substrate100 by a method such as a sputtering method or a vapor depositionmethod. The conductive layer 201 may be formed to have a film thicknessof from 0.01 nm to 10 nm, however, a layer structure is not necessarilyneeded since it may be formed extremely thin. Note that this base layer201 is provided to form the gate electrode with good adhesiveness. Whenadequate adhesiveness is obtained, the gate electrode may be directlyformed on the substrate 100 by a droplet discharge method withoutforming the base layer 201.

A gate wiring 202, a gate electrode 203, a capacitor electrode 204, anda gate electrode 205 are formed on the base layer 201 by discharging acomposition containing a conductive material with a droplet dischargemethod. The composition containing particles of a metal such as Ag(silver), Au (gold), Cu (copper), W (tungsten), or Al (aluminum) as themain component can be used as the conductive material which forms theselayers. Specifically, the gate wiring is preferable to be lowresistance. Therefore, a material in which any one of gold, silver, orcopper dissolved or dispersed in a solvent is preferably used, and morepreferably silver or copper with low resistance is used in considerationof a specific resistance value. Since the gate electrode needs to beformed minutely, a nano paste containing particles of which averageparticle size is from 5 nm to 10 nm is preferably used.

In addition, the gate electrode may be formed by discharging acomposition containing particles covered the circumference of aconductive material with other conductive materials. For example, as forparticle covered the circumference of Cu with Ag, a conductive particleprovided with a buffer layer made from Ni or NiB (nickel boron) betweenCu and Ag may be used. A solvent corresponds to esters such as butylacetate, alcohols such as isopropyl alcohol, an organic solvent such asacetone, or the like. Surface tension and viscosity are appropriatelyadjusted by adjusting density of a solution and adding a surfaceactivator.

A diameter of a nozzle used in a droplet discharge method is set to befrom 0.02 μm to 100 μm (preferably, 30 μm or less), and a dischargingamount of a composition discharged from the nozzle is preferably set tobe from 0.001 pl to 100 pl (preferably, 10 pl or less). There are twotypes of an on-demand type and a continuous type for a droplet dischargemethod, both of which may be used. Furthermore, there is a piezoelectricsystem using properties transformed by applying voltage pressure of apiezoelectric material and a heating system that boils a composition bya heater provided in a nozzle and discharges the composition for anozzle to be used in a droplet discharge method, both of which may beused. A distance between a subject and a discharge opening of a nozzleis preferable to be made as close as possible to drop a droplet at adesired place, which is preferably set to be from 0.1 mm to 3 mm(preferably, 1 mm or less). While keeping the relative distance, one ofthe nozzle and the subject moves and a desired pattern is drawn. Inaddition, plasma treatment may be carried out on a surface of thesubject before discharging a composition. This is to take advantage of asurface of the subject becoming hydrophilic and lyophobic when plasmatreatment is carried out. For example, it becomes hydrophilic todeionized water and it becomes lyophobic to a paste dissolved withalcohol.

A step of discharging a composition may be carried out under lowpressure so that a solvent of the composition can be volatilized whilethe composition is discharged and land in a subject and later steps ofdrying and baking can be skipped or shorten. In a baking step of acomposition containing a conductive material, resistivity of aconductive film including the gate electrode can be decreased and theconductive film can be made thin and smoothed by actively using a gasmixed with oxygen of which division ratio is from 10% to 30%.

After discharging a composition, either or both steps of drying andbaking is carried out by irradiation of laser light, rapid thermalannealing, heating furnace, or the like under the atmospheric pressureor the low pressure. Both the steps of drying and baling are steps ofheat treatment. For example, drying is carried out at 100° C. for 3minutes and baking is carried out at temperatures from 200° C. to 350°C. for from 15 minutes to 120 minutes. In order to carry out the stepsof drying and baking well, a substrate may be heated, of whichtemperatures are set to be from 100° C. to 800° C. (preferably,temperatures from 200° C. to 350° C.), though depending on a material ofa substrate or the like. Through this step, a solvent in a compositionis volatilized or dispersant is removed chemically, and a resin aroundcures and shrink, thereby accelerating fusion and welding. It is carriedout under the oxygen atmosphere, the nitrogen atmosphere, or theatmosphere. However, this step is preferable to be carried out under anoxygen atmosphere in which a solvent decomposing or dispersing a metalelement is easily removed.

A continuous-wave or pulsed gas laser or solid state laser may be usedfor irradiation of laser light. There is an excimer laser, or the likeas the gas laser, and there is a laser using a crystal such as YAG orYVO₄ doped with Cr, Nd, or the like as the solid state laser. It ispreferable to use a continuous-wave laser in terms of the laser lightabsorptance. In addition, a so-called hybrid method of laser irradiationcombining a continuous oscillation and a pulsed oscillation may be alsoused. However, heat treatment by irradiation of laser light may becarried out rapidly from some microseconds to some ten seconds dependingon the heat resistance of a substrate. Rapid Thermal Annealing (RTA) iscarried out by applying heat rapidly from some microseconds to someminutes by rapidly raising temperature with the use of an infrared lampthat emits light from ultraviolet light to infrared light, a halogenlamp, or the like under the atmosphere of inert gas. This treatment iscarried out rapidly; therefore, substantially, only a thin film on anuppermost surface can be heated, and thus, there is advantage that thelower layer is not affected.

A nano paste is a conductive particle, of which particle size is from 5nm to 10 nm, that is dispersed or dissolved in an organic solvent, and adispersant or a thermosetting resin referred to as a binder is containedas well. A binder has a function of preventing generation of crack oruneven baked state during baking. According to the drying or bakingstep, evaporation of the organic solvent, decomposition and removal ofthe dispersant, and hardening shrinkage by a binder are carried outsimultaneously; therefore, nanoparticles makes fusion and/or weldingwith each other to be hardened. In this case, the nanoparticles is grownfrom several tens nm to several hundreds nm. The grown particles closeto each other makes fusion and/or welding to connect in chain with eachother to form a metal chain body. On the other hand, almost allremaining organic component (approximately from 80% to 90%) is pushed tooutside of the metal chain body. As a result, a conductive filmcontaining the metal chain body and a film made from an organiccomponent covering the outside of the conductive film are formed. Inaddition, oxygen contained in a gas is reacted with carbon, hydrogen, orthe like contained in the film made from an organic component when anano paste is baked under the atmosphere containing nitrogen and oxygen;therefore, the film made from an organic component can be removed.

In addition, when oxygen is not contained in the baking atmosphere, thefilm made from an organic component can be removed by additionallycarrying out oxygen plasma treatment or the like. In this manner, thefilm made from an organic component is removed by baking a nano pasteunder the atmosphere containing nitrogen and oxygen or by carrying outoxygen plasma treatment after drying. Therefore, the conductive filmcontaining the remaining metal chain body can be made smoothed, thin, orreduced in resistance since the film made from an organic component isremoved. A solvent in a composition containing a conductive materialvolatilizes by discharging the composition under the low pressure;therefore, the time for subsequent heat treatment (drying or baking) canbe shortened.

After forming the gate wiring 202, the gate electrode 203, the capacitorelectrode 204, and the gate electrode 205, it is desirable to carry outone of the following two steps as treatment of the base layer 201 ofwhich surface is exposed.

A first method is a step of forming an insulating layer 206 byinsulating the base layer 201 not overlapping with the gate wiring 202,the gate electrode 203, the capacitor electrode 204, and the gateelectrode 205 (see FIG. 4B). In other words, the base layer 201 notoverlapping with the gate wiring 202, the gate electrode 203, thecapacitor electrode 204, and the gate electrode 205 are oxidized to beinsulated. In the case of insulating the base layer 201 by oxidizing inthis manner, the base layer 201 is preferably formed to have a filmthickness of from 0.01 nm to 10 nm, so that it can be easily oxidized.Note that either an exposing method to the oxygen atmosphere or a methodfor carrying out heat treatment may be used as an oxidizing method.

A second method is a step of etching and removing the base layer 201,using the gate wiring 202, the gate electrode 203, the capacitorelectrode 204, and the gate electrode 205 as the masks. In the case ofusing this step, there is no restriction on a film thickness of the baselayer 201.

Next, a gate insulating layer 207 is formed in a single layer or alaminated structure by using a plasma CVD method or a sputtering method(see FIG. 4C). As a specifically preferable mode, a lamination body ofthree layers of a first insulating layer 208 made from silicon nitride,a second insulating layer 209 made from silicon oxide, and a thirdinsulating layer 210 made from silicon nitride is composed as the gateinsulating film. Note that a rare gas such as argon may be contained ina reactive gas and mixed into an insulating film to be formed in orderto form a dense insulating film with little gate leak current at a lowdeposition temperature. Deterioration by oxidation can be prevented byforming the first insulating layer 208 being in contact with the gatewiring 202, the gate electrode 203, the capacitor electrode 204, and thegate electrode 205 preferably from silicon nitride or silicon nitrideoxide.

Next, a semiconductor layer 211 is formed. The semiconductor layer 211is formed from an AS manufactured with a vapor phase growth method or asputtering method by using a semiconductor material gas typified bysilane or germane or from an SAS. A plasma CVD method or a thermal CVDmethod can be used as a vapor phase growth method.

In the case of using a plasma CVD method, an AS is formed from SiH₄which is a semiconductor material gas or a mixed gas of SiH₄ and H₂.When SiH₄ is diluted with H₂ by from 3 times to 1000 times to make amixed gas or when Si₂H₆ is diluted with GeF₄ so that a gas flow rate ofSi₂H₆ to GeF₄ is from 20 to 40 to 0.9, an SAS of which Si compositionratio is 80% or more can be obtained. Specifically, the latter case ispreferable since the semiconductor layer 211 can have crystallinity froman interface with the third insulating layer.

An insulating layer 212 is formed on the semiconductor layer 211 by aplasma CVD method or a sputtering method. As shown in the followingsteps, this insulating layer 212 is left on the semiconductor layer 211being opposed to the gate electrode and serves as a channel protectivelayer. The semiconductor layer 211 is preferably formed of a dense filmin order to prevent external impurities such as metal or an organicmaterial and to keep clean an interface between the insulating layer 212and the semiconductor layer 211. It is desirable that this insulatinglayer 212 can be formed at low temperature. For example, in a glowdischarge decomposition method, a silicon nitride film which is formedby diluting a silicide gas by from 100 times to 500 times with a raregas such as argon is preferable since the dense film can be formed evenat a deposition temperature of 100° C. or less.

It is possible to continuously form the gate insulating layer 207 to theinsulating layer 212 without exposing to the atmosphere. In other words,each interface between laminated layers can be formed without beingcontaminated by an atmospheric constituent and an airborne contaminatedimpurity element that is floated in an atmosphere; therefore, variationsin properties of a TFT can be decreased.

Next, a mask 213 is formed by selectively discharging a composition at aposition that is opposed to the gate electrode 203 and the gateelectrode 205 and that is on the insulating layer 212 (see FIG. 4C). Aresin material such as an epoxy resin, an acrylic resin, a phenol resin,a novolac resin, a melamine resin, or a urethane resin is used for themask 213. In addition, the mask 213 is formed with a droplet dischargemethod by using an organic material such as benzocyclobutene, parylene,flare, or light-transmitting polyimide; a compound material made frompolymerization such as siloxane-based polymer; a composition materialcontaining water-soluble homopolymer and water-soluble copolymer; or thelike. Alternatively, a commercial resist material containing aphotosensitizer may be used. For example, a typical positive type resistcomprising a novolac resin and naphthoquinonedi azide compound that is aphotosensitizer, a negative type resist comprising a base resin,diphenylsilane diol, and an acid generation agent, or the like may beused. In using any one of materials, surface tension and viscosity areappropriately adjusted by diluting density of a solution or adding asurface activator or the like.

The insulating layer 212 is etched by using the mask 213 as shown inFIG. 4C, and an insulating layer 214 functioning as a channel protectivelayer is formed (see FIG. 5A). An n-type semiconductor layer 215 isformed over the semiconductor layer 211 and the insulating layer 214 byremoving the mask 213. The n-type semiconductor layer 215 may be formedby using a silane gas and a phosphine gas and can be formed from an ASor an SAS.

Next, a mask 216 is formed with a droplet discharge method on the n-typesemiconductor layer 215. By using this mask 216, the n-typesemiconductor layer 215 and the semiconductor layer 211 are etched, anda semiconductor layer 217 and an n-type semiconductor layer 218 areformed (see FIG. 5B). Note that FIG. 5B schematically shows alongitudinal sectional structure, and FIG. 9 shows a planar structurecorresponding to A-B and C-D thereof.

Next, a through hole 219 is formed in a part of the gate insulatinglayer 207 by an etching process, and the gate electrode 205 disposed inthe lower layer thereof is partially exposed (see FIG. 5C). The etchingprocess may be carried out by forming the same mask as the above with adroplet discharge method. Either plasma etching or wet etching may beapplied for the etching process. Plasma etching is appropriate forprocessing a large-sized substrate. A fluorine-based or chlorine-basedgas such as CF₄, NF₃, Cl₂, or BCl₃ is used for an etching gas, and He orAr may be added appropriately. In addition, when an etching process ofatmospheric pressure discharge is applied, a local discharge process isalso possible; therefore, there is no necessity to form a mask over anentire surface of a substrate.

Subsequently, wirings 220, 221, 222, and 223 connected to a source and adrain are formed with a droplet discharge method by selectivelydischarging a composition containing a conductive material (see FIG.6A). FIG. 6A shows a longitudinal sectional structure, and FIG. 10 showsa planar structure corresponding to A-B and C-D shown in FIG. 6A. Asshown in FIG. 10, a wiring 240 extending from one end of a substrate 100is simultaneously formed. This is provided to electrically connect to awiring 220. In addition, as shown in FIG. 6A, the wiring 221 and thegate electrode 205 are electrically connected in the through hole 219formed in the gate insulating layer 207. A composition containingparticles of a metal such as Ag (silver), Au (gold), Cu (copper), W(tungsten), or Al (aluminum) as the main component can be used as aconductive material which forms this wiring. Furthermore,light-transmitting indium tin oxide (hereinafter also referred to as an“ITO”), indium tin oxide containing silicon oxide (hereinafter alsoreferred to as an “ITSO”), organic indium, organotin, zinc oxide,titanium nitride, and the like may be combined.

Next, using the wirings 220, 221, 222, and 223 as the masks, n-typesemiconductor layers 224 and 225 which forms source and drain regionsare formed by etching the n-type semiconductor layer 218 on theinsulating layer 214 (see FIG. 6B).

A first electrode 226 corresponding to a pixel electrode is formed byselectively discharging a composition containing a conductive materialso that it is electrically connected to the wiring 223 (see FIG. 6C).Note that FIG. 6C shows a longitudinal sectional structure and FIG. 11shows a planar structure corresponding to A-B and C-D thereof. Throughabove-mentioned steps, switching TFT 231, a driving TFT 232, and acapacitor portion 233 are formed.

This first electrode 226 is formed by using a droplet discharge method.In the case of manufacturing a transmission type EL display panel, acomposition containing indium tin oxide (ITO), indium tin oxidecontaining silicon oxide (ITSO), zinc oxide, tin oxide, or the like maybe used for the first electrode 226. Then, a predetermined pattern maybe formed and a pixel electrode may be formed by baking.

The first electrode 226 is formed from indium tin oxide (ITO), indiumtin oxide containing silicon oxide (ITSO), zinc oxide (ZnO), or the likeby a sputtering method. More preferably, indium tin oxide containingsilicon oxide is used with a sputtering method by using a target inwhich 2 wt. % to 10 wt. % of silicon oxide is contained in ITO.Moreover, conductive oxide containing silicon oxide and in which 2 wt. %to 20 wt. % of zinc oxide is mixed with indium oxide (hereinafter, alsoreferred to as “IZO”) may be used.

The first electrode 226 formed from indium tin oxide containing siliconoxide is formed very close to the third insulating layer 210 made fromsilicon nitride contained in the gate insulating layer 207. Thisstructure can decrease the loss of light when light is radiated on theside of the substrate 100 through the first electrode 226.

In addition, a composition containing particles of a metal such as Ag(silver), Au (gold), Cu (copper), W (tungsten), or Al (aluminum) can beused for the first electrode 226 in the case of a structure in whichlight is radiated on the side opposite to the substrate 100.

Furthermore, a protective layer 227 of silicon nitride or siliconnitride oxide and an insulating layer 228 are entirely formed. Aninsulator that can be formed by an application method such as a spincoating method or a dip method may be applied to the insulating layer228; The protective layer 227 and the insulating layer 228 are formed tocover the edge of the first electrode 226. A structure of the protectivelayer 227 and the insulating layer 228 shown in FIG. 6C can be formed byan etching process, and thus, the surface of the first electrode 226 isexposed. The first electrode 226 and the gate wiring 202 are processedto be exposed by this etching by simultaneously etching the protectivelayer 227 in the lower layer of the insulating layer 228 and the gateinsulating layer 207.

The insulating layer 228 is formed by providing an opening having athrough hole in accordance with a position where a pixel is formed bycorresponding to the first electrode 226. This insulating layer 228 canbe formed from an inorganic insulating material such as silicon oxide,silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride,aluminum oxynitride, or the like; acrylic acid, methacrylic acid, and aderivative thereof; a high molecular weight material having heatresistance such as polyimide, aromatic polyamide, or polybenzimidazole;inorganic siloxane including a Si—O—Si bond, among the compound madefrom silicon, oxygen, and hydrogen, formed by using a siloxane-basedmaterial as a start material; or an organic siloxane insulating materialin which hydrogen over silicon is substituted by an organic group suchas methyl or phenyl. When the insulating layer 228 is formed from aphotosensitive material or a non-photosensitive material such as acrylicor polyimide, it is preferable since the edge thereof has a shape inwhich a curvature radius changes continuously and a thin film in theupper layer is formed without a step disconnection.

Through the above-mentioned steps, a TFT substrate 200 for an EL displaypanel in which a bottom gate type (also referred to as a reverse staggertype) TFT and the first electrode are connected over the substrate 100is completed.

FIG. 7 shows a mode in which an EL layer 229 is formed over the TFTsubstrate 200 and combined with a sealing substrate 236. Before formingthe EL layer 229, heat treatment at 100° C. or more under theatmospheric pressure is carried out to remove the moisture adsorbed inthe insulating layer 228 or on the surface thereof. In addition, heattreatment is carried out at temperatures from 200° C. to 400° C.,preferably from 250° C. to 350° C. under the low pressure. It ispreferable to form the EL layer 229 with a vacuum vapor depositionmethod or a droplet discharge method under the low pressure withoutexposing to the atmosphere.

In addition, surface treatment may be additionally carried out byexposing the surface of the first electrode 226 to oxygen plasma orirradiating it with ultraviolet light. A second electrode 230 is formedon the EL layer 229 to form a light-emitting element 234. Thislight-emitting element 234 has a structure in which it is connected tothe driving TFT 232.

Subsequently, a sealant 235 is formed and sealed by using the sealingsubstrate 236. Thereafter, a flexible wiring board 237 may be connectedto the gate wiring 202 (see FIG. 7).

As mentioned above, in this embodiment mode, a display device combininglight-emitting elements can be manufactured by manufacturing a TFTwithout using a light-exposure step using a photomask. A part or all ofthe treatment such as application of a resist, light-exposure, ordevelopment according to the light-exposure step can be skipped. Inaddition, an EL display panel can be easily manufactured even by using aglass substrate after five generations, one side of which exceeds 1000mm by forming each kind of pattern directly on a substrate by using adroplet discharge method.

Embodiment Mode 2

A method for manufacturing a channel etch type TFT and a display devicewith the use thereof are explained in Embodiment Mode 2.

A gate wiring 202, a gate electrode 203, a capacitor electrode 204, anda gate electrode 205 are formed over a substrate 100 by discharging acomposition containing a conductive material by a droplet dischargemethod. Next, a gate insulating layer 207 is formed to have a singlelayer structure or a laminated structure by a plasma CVD method or asputtering method. The gate insulating layer 207 may be formed fromsilicon nitride or silicon oxide in the same manner as EmbodimentMode 1. Furthermore, a semiconductor layer 211 functioning as an activelayer is formed. The above-mentioned steps are the same as those inEmbodiment Mode 1.

An n-type semiconductor layer 215 is formed on the semiconductor layer211 (see FIG. 12A). Next, a mask 302 is formed by selectivelydischarging a resist composition on the n-type semiconductor layer 215.Subsequently, the semiconductor layer 211 and the n-type semiconductorlayer 215 are etched by using the mask 302.

Wirings 220, 221, 222, and 223 are formed by discharging a compositioncontaining a conductive material in accordance with a disposition of thesemiconductor layers separated by etching. The n-type semiconductorlayer is etched by using the wirings as the masks. N-type semiconductorlayers 224 and 225 left on a part overlapping with the wirings 220, 221,222, and 223 serve as layers including a region operating as a source ora drain. A semiconductor layer 303 includes a region where a channel isformed and is formed to be in contact with the n-type semiconductorlayers 224 and 225. As well as in Embodiment Mode 1, a through hole 219is formed in a part of the gate insulating layer 207 and a step ofpartially exposing the gate electrode 205 disposed in the lower layerside is carried out before this etching process. Accordingly, aconnection structure of the wiring 221 and the gate electrode 205 can beformed (see FIG. 12B).

Subsequently, a first electrode 226 is formed by discharging acomposition containing a conductive material to electrically connect tothe wiring 223 (see FIG. 12C).

Thereafter, as well as in Embodiment Mode 1, a protective layer 227, aninsulating layer 228, an EL layer 229, and a second electrode 230 areformed. Furthermore, a sealant 235 is formed and sealed by using asealing substrate 236. Thereafter, a flexible wiring board 237 may beconnected to the gate wiring 202. As mentioned above, an EL displaypanel having a display function can be manufactured (see FIG. 13).

Embodiment Mode 3

In an EL display panels manufactured by Embodiment Mode 1 and EmbodimentMode 2, as explained in FIG. 3, a scanning line driver circuit can beformed on a substrate 100 by forming a semiconductor layer from an SAS.

FIG. 22 shows a block diagram of the scanning line driver circuitcomposed of n-channel type TFTs using the SAS in which electric fieldeffect mobility of from 1 cm²/V·sec to 15 cm²/V·sec is obtained.

In FIG. 22, a pulse output circuit 500 is a circuit outputting asampling pulse for one stage and includes a shift register. The pulseoutput circuit 500 is connected to a buffer circuit 501 and connected toa pixel 502 (corresponds to a pixel 102 in FIG. 3) at the end thereof.

FIG. 23 shows a specific structure of the pulse output circuit 500, andthis pulse output circuit 500 is composed of n-channel type TFTs 601 to613. The size of the TFTs may be decided by the pulse output circuit 500in consideration of an operating characteristic of the n-channel typeTFTs using an SAS. For example, when a channel length is set to be 8 μm,the channel width can be set ranging from 10 μm to 80 μm.

In addition, FIG. 24 shows a specific structure of the buffer circuit501. The buffer circuit is composed of n-channel type TFTs 620 to 635 inthe same manner. At this time, the size of the TFTs may be decided inconsideration of an operating characteristic of the n-channel type TFTsusing an SAS. For example, when a channel length is set to be 10 μm, thechannel width can be set ranging from 10 μm to 1800 μm.

It is necessary to connect the TFTs with each other by wirings torealize such a circuit, and FIG. 14 shows a structure example of wiringsin the case thereof. As well as in Embodiment Mode 1, FIG. 14 shows astate in which a gate electrode 203, a gate insulating layer 207 (alamination body of three layer including a first insulating layer 208containing silicon nitride, a second insulating layer 209 containingsilicon oxide, and a third insulating layer 210 containing siliconnitride), a semiconductor layer 217 formed from an SAS, an insulatinglayer 214 which forms a channel protective layer, n-type semiconductorlayers 224 and 225 which forms a source and a drain, and wirings 220 and221 are formed. In this case, connection wirings 250, 251, and 252 areformed over the substrate 100 in the same step as in that of the gateelectrode 203. An etching process is partly carried out on the gateinsulating layer so that the connection wirings 250, 251, and 252 areexposed. Accordingly, various kinds of circuits can be realized byconnecting the TFTs appropriately by the wirings 220 and 221 and aconnection wiring 253 formed in the same step.

Embodiment Mode 4

A top gate type TFT manufactured by a droplet discharge method isexplained in Embodiment Mode 4 with reference to FIG. 26 and FIG. 31.

Wirings 271, 272, 273, 274, and 275 are formed over a substrate 100 by adroplet discharge method. A composition containing particles of a metalsuch as Ag (silver), Au (gold), Cu (copper), W (tungsten), or Al(aluminum) as the main component can be used for the conductive materialwhich forms these layers. Specifically, the wirings connected to asource and a drain are preferable to be low resistance. Therefore, amaterial in which any one of gold, silver, or copper dissolved ordispersed in a solvent is preferably used, and more preferably silver orcopper with low resistance is used in consideration of a specificresistance value. A solvent corresponds to an organic solvent such asesters such as butyl acetate, alcohols such as isopropyl alcohol,acetone, or the like. Surface tension and viscosity is appropriatelyadjusted by adjusting density of a solution and adding a surfaceactivator or the like. As well as in Embodiment Mode 1, a base layer maybe provided.

After forming an n-type semiconductor layer on the entire surface of thewirings 272, 273, 274, and 275 connected to the source and the drain,the n-type semiconductor layer between the wirings 272 and 273, thewirings 274 and 275 are removed by etching. Then, an AS or an SAS isformed with a vapor phase growth method or a sputtering method. When aplasma CVD method is used, an AS is formed by using SiH₄ which is asemiconductor material gas or a mixed gas of SiH₄ and H₂. An SAS isformed from the mixed gas by diluting SiH₄ with H₂ by from 3 times to1000 times. Thereafter, the AS or the SAS and the n-type semiconductorlayer are etched. Accordingly, a semiconductor layer 278 and n-typesemiconductor layers 276 and 277 are formed. When an SAS is formed, thecrystallinity is more satisfactory on a side of the surface of thesemiconductor layer 278, and a combination with a top gate type TFT inwhich gate electrodes 279 and 280 are formed over the semiconductorlayer 278 is suitable.

The semiconductor 278 is formed in a position corresponding to thewirings 272, 273, 274, and 275 by using a mask formed by a dropletdischarge method. In other words, the semiconductor layer 278 is formedto overlap with the wirings 272 and 273 (or the wirings 274 and 275). Atthis time, the n-type semiconductor layers 276 and 277 are sandwichedbetween the semiconductor layer 278 and the wirings 272, 273, 274, and275.

Then, a gate insulating layer 207 is formed to have a single layerstructure or a laminated structure by using a plasma CVD method or asputtering method. In the same manner as Embodiment Mode 1, the gateinsulating layer 207 may be formed by using silicon nitride and siliconoxide. Furthermore, a semiconductor layer 211 functioning as an activelayer is formed. The above-mentioned steps are the same as that inEmbodiment Mode 1.

After forming a through hole in the gate insulating layer 207 andpartially exposing the wirings 273 and 275, the gate electrodes 279 and280 are formed with a droplet discharge method. A composition containingparticles of a metal such as Ag (silver), Au (gold), Cu (copper), W(tungsten), or Al (aluminum) as the main component can be used for aconductive material which forms this layer.

A first electrode 226 is formed by selectively discharging a compositioncontaining a conductive material to be electrically connected to thewiring 275. The first electrode 226 can serve as a pixel electrode of adisplay device. Through the above-mentioned steps, a TFT substrate overwhich a switching TFT 291, a driving TFT 292, and a capacitor portion293 are formed can be obtained.

This first electrode 226 can be formed by using a droplet dischargemethod in the case of manufacturing a transmission type EL displaydevice, the first electrode 226 may form a predetermined pattern from acomposition containing indium tin oxide (ITO), indium tin oxidecontaining silicon oxide (ITSO), zinc oxide, tin oxide, or the like andmay form a pixel electrode by baking.

It is preferably formed from indium tin oxide (ITO), indium tin oxidecontaining silicon oxide (ITSO), zinc oxide, or the like by a sputteringmethod. More preferably, indium tin oxide containing silicon oxide isused with a sputtering method by using a target in which 2 wt. % to 10wt. % of silicon oxide is contained in ITO.

As a preferable structure of this embodiment mode, the first electrode226 formed from indium tin oxide containing silicon oxide is formedclosely in contact with a third insulating layer 210 made from siliconnitride contained in the gate insulating layer 207. Accordingly, aneffect of increasing a ratio of light generated in an EL layer to beradiated outside can be realized.

Furthermore, an insulating layer 228 is formed over the entire surface.After forming the insulating layer over the entire surface by a spincoating method or a dip method, an opening is formed in the insulatinglayer 228 by an etching process as shown in FIG. 26. The first electrode226 and the wiring 271 are processed to be exposed by this etching bysimultaneously etching the protective layer 227 in the lower layer ofthe insulating layer 228 and the gate insulating layer 207. In addition,when the insulating layer 228 is formed by a droplet discharge method,an etching process is not necessarily needed.

The insulating layer 228 is formed by providing an opening having athrough hole in accordance with a position where a pixel is formed bycorresponding to the first electrode 226. This insulating layer 228 canbe formed from an inorganic insulating material such as silicon oxide,silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride,aluminum oxynitride, or the like; acrylic acid, methacrylic acid, and aderivative thereof; a high molecular weight material having heatresistance such as polyimide, aromatic polyamide, or polybenzimidazole;inorganic siloxane including a Si—O—Si bond, among the compound madefrom silicon, oxygen, and hydrogen, formed by using a siloxane-basedmaterial as a start material; or an organic siloxane insulating materialin which hydrogen over silicon is substituted by an organic group suchas methyl or phenyl. When the insulating layer 228 is formed from aphotosensitive material or a non-photosensitive material such as acrylicor polyimide, it is preferable since the edge thereof has a shape inwhich a curvature radius changes continuously and a thin film in theupper layer is formed without a step disconnection.

Through the above-mentioned steps, a TFT substrate for an EL displaypanel in which a top gate type (also referred to as a forward staggertype) TFT and the first electrode are connected over the substrate 100is completed.

Thereafter, an EL layer 229 is formed and a sealing substrate 236 iscombined. Before forming the EL layer 229, heat treatment at 200° C.under the atmospheric pressure is carried out to remove the moistureadsorbed in the insulating layer 228 or on the surface thereof. Inaddition, heat treatment is carried out at temperatures from 200° C. to400° C., preferably from 250° C. to 350° C. under the low pressure. Itis preferable to form the EL layer 229 with a vacuum vapor depositionmethod or a droplet discharge method under the low pressure withoutexposing to the atmosphere.

Furthermore, a second electrode 230 is formed on the EL layer to form alight-emitting element 234. This light-emitting element 234 has astructure in which it is connected to the driving TFT 292.

Subsequently, a sealant 235 is formed and the sealing substrate 236 isfixed. Thereafter, a flexible wiring board 237 may be connected to thewiring 271.

As mentioned above, a light-exposure step using a photomask is not usedin this embodiment mode; therefore, the step can be skipped. Inaddition, a display device can be easily manufactured even by using aglass substrate after five generations, one side of which exceeds 1000mm by forming each kind of pattern directly on a substrate by using adroplet discharge method.

Embodiment Mode 5

A mode of a light-emitting element applicable to Embodiment Mode 1 toEmbodiment Mode 4 is explained with reference to FIGS. 17A and 17B andFIGS. 18A and 18B.

FIG. 17A is an example in which a first electrode 801 is formed from alight-transmitting oxide conductive substance. The light-transmittingconductive oxide substance is preferable to be indium tin oxidecontaining 1 atomic % to 15 atomic % of silicon oxide in concentration.An EL layer 802 in which a hole injection layer or hole transport layer804, a light-emitting layer 805, and an electron transport layer orelectron injection layer 806 are laminated thereover is provided. Asecond electrode 803 is formed of a first electrode layer 807 containingan alkaline metal or an alkaline earth metal, for example, LiF or MgAgand a second electrode layer 808 formed from a metal material such asaluminum. The pixel having such a structure can radiate light from thefirst electrode 801 side as shown in figure with an arrow.

FIG. 17B shows an example of radiating light from a second electrode803. A first electrode 801 is formed of a first electrode layer 809formed from a metal such as aluminum or titanium or a conductivematerial containing the metal and nitrogen of which concentration is ina stoichiometric composition ratio or less and a second electrode layer810 formed from a conductive oxide material containing 1 atomic % to 15atomic % of silicon oxide in concentration. An EL layer 802 in which ahole injection layer or hole transport layer 804, a light-emitting layer805, and an electron transport layer or electron injection layer 806 arelaminated thereover is provided. A second electrode 803 is formed of afirst electrode layer 807 containing an alkaline metal or an alkalineearth metal, for example, LiF or CaF and a second electrode layer 808formed from a metal material such as aluminum. However, any one oflayers is kept in a state in which light can be transmitted by makingthe thickness 100 nm or less. Accordingly, it is possible to radiatelight from the second electrode 803.

FIG. 18A shows an example of radiating light from a first electrode 801and shows a structure in which an electron transport layer or electroninjection layer 806, a light-emitting layer 805, and a hole injectionlayer or hole transport layer 804 are sequentially laminated in an ELlayer. From an EL layer 802 side, a second electrode 803 is formed of asecond electrode layer 810 formed from a conductive oxide materialcontaining 1 atomic % to 15 atomic % of silicon oxide in concentrationand a first electrode layer 809 formed from a metal such as aluminum ortitanium or a metal containing nitrogen of which concentration is in astoichiometric composition ratio or less. The first electrode 801 isformed from a first electrode layer 807 containing an alkaline metal oran alkaline earth metal, for example, LiF or CaF and a second electrodelayer 808 formed from a metal material such as aluminum. However, anyone of layers is kept in a state in which light can be transmitted bymaking the thickness 100 nm or less. Accordingly, it is possible toradiate light from the first electrode 801.

FIG. 18B shows an example of radiating light from a second electrode 803and shows a structure in which an electron transport layer or electroninjection layer 806, a light-emitting layer 805, and a hole injectionlayer or hole transport layer 804 are sequentially laminated in an ELlayer. A first electrode 801 has the same structure as FIG. 18A and isformed thick so as to have a film thickness enough to reflect lightemitted in the EL layer. The second electrode 803 is composed of aconductive oxide material containing 1 atomic % to 15 atomic % ofsilicon oxide in concentration. In this structure, the hole injectionlayer or hole transport layer 804 is formed from metallic oxide which isan inorganic substance (typically, molybdenum oxide or vanadium oxide).Accordingly, oxygen introduced at the time of forming the secondelectrode 803 is supplied and hole injection properties are improved;therefore, a drive voltage can be decreased.

Embodiment Mode 6

Next, a mode of mounting a driver circuit for driving on an EL displaypanel manufactured by Embodiment Mode 1, Embodiment Mode 2, andEmbodiment Mode 3 is explained with reference to FIGS. 19A and 19B andFIGS. 20A and 20B.

First, a display device to which a COG method is applied is explainedwith reference to FIGS. 19A and 19B. FIGS. 19A and 19B each show adisplay device in which a pixel portion 1002 displaying information suchas a character or an image and scanning line driver circuits 1003 and1004 are provided on a substrate 1001.

In FIG. 19A, individual driver circuit (hereinafter referred to as adriver IC) is taken out and mounted by separating a large-sizedsubstrate 1005 on which a plurality of driver circuits is formed. Thelarge-sized substrate 1005 may be the same as a glass substrate used fora display device. Driver ICs 1007 can be obtained by forming a pluralityof driver ICs on a rectangular substrate of which one side is, forexample, from 300 mm to 1000 mm or more and by separating it. The driverICs 1007 are separated by forming it in a rectangular shape of whichmajor axis is from 15 mm to 80 mm and minor axis is from 1 mm to 6 mm inconsideration of a length of one side of the pixel portion or a pixelpitch. Apart cost can be reduced by forming the driver ICs on thelarge-sized substrate 1005 with a TFT using a crystalline semiconductorfilm.

FIG. 19A shows a mode in which a plurality of the driver ICs 1007 ismounted on the substrate 1001 and has a structure in which a signal isinputted from an external circuit by connecting a flexible wiring 1006at the end of the driver ICs 1007. FIG. 19B shows a structure in which along driver IC 1010 cut from a large-sized substrate 1008 is mounted onthe substrate 1001. A mode in which a flexible wiring 1009 is mounted onat the end of the long driver IC 1010 is shown. The number of parts canbe reduced and the number of steps can be reduced by using such a longdriver IC.

Next, a display device to which a TAB method is adopted is explainedwith reference to FIGS. 20A and 20B. A pixel portion 1002 and scanningline driver circuits 1003 and 1004 are provided on a substrate 1001. InFIG. 20A, a plurality of flexible wirings 1006 is attached to thesubstrate 1001. Driver ICs 1007 are mounted on the flexible wirings1006. FIG. 20B shows a mode in which a flexible wiring 1009 is attachedon the substrate 1001 and a driver IC 1010 is mounted on the flexiblewiring 1009. In the case of applying the latter, metal pieces or thelike that fixes the driver IC 1010 may be attached together in respectof intensity. The number of parts can be reduced and the number of stepscan be reduced by using such a long driver IC.

The restriction specifically on a length of a major axis is relieved byforming the driver IC on the glass substrate as in FIGS. 19A and 19B andFIGS. 20A and 20B, and less number necessary for mounting correspondingto the pixel portion 1002 is achieved. In other words, a long driver ICcannot be formed of a driver IC formed from single crystal silicon dueto mechanical strength or restriction of a substrate. When a driver ICis formed on a glass substrate, the driver IC does not lose productivitysince it is not limited to a shape of a substrate used as a mother body.This is a large predominant respect as compared with the case of takingout IC chips from a circular silicon wafer.

The driver IC 1007 shown in FIGS. 19A and 19B and FIGS. 20A and 20B aresignal line driver circuits. In order to form a pixel portioncorresponding to a RGB full color, 3072 signal lines in a XGA class and4800 signal lines in a UXGA class are necessary. The signal line formedin such a number forms a leading out line by dividing into severalblocks on an edge of the pixel portion 1002 and is gathered inaccordance with a pitch of an output terminal of the driver IC 1007.

The driver ICs are preferably formed from a crystalline semiconductorformed over a substrate. The crystalline semiconductor is preferable tobe formed by being irradiated with a continuous-wave laser. Therefore, acontinuous-wave solid state laser or gas laser is used as an oscillatorin which the laser light is generated. There is few crystal defects whena continuous-wave laser is used, and as a result, a transistor can bemanufactured by using a polycrystalline semiconductor layer with a largegrain size. In addition, high-speed driving is possible since mobilityor a response speed is favorable, and it is possible to further improvean operating frequency of an element than that of the conventionalelement; therefore, high reliability can be obtained since there is fewproperties variations. Note that a channel-length direction of atransistor and a scanning direction of laser light may be accorded witheach other to further improve an operating frequency. This is becausethe highest mobility can be obtained when a channel length direction ofa transistor and a scanning direction of laser light with respect to asubstrate are almost parallel (preferably, from −30° to 30°) in a stepof laser crystallization by a continuous-wave laser. A channel lengthdirection coincides with a direction of current floating in a channelformation region, in other words, a direction in which an electriccharge moves. The transistor thus manufactured has an active layercomposed of a polycrystalline semiconductor layer in which a crystalgrain is extended in a channel direction, and this means that a crystalgrain boundary is formed almost along a channel direction.

In carrying out laser crystallization, it is preferable to narrow downthe laser light largely, and a beam spot thereof preferably has a widthof approximately from 1 mm to 3 mm of which width is the same as that ofa minor axis of the driver ICs. In addition, in order to ensure anobject to be irradiated an enough and effective energy density, anirradiated region of the laser light is preferably a linear shape.However, a linear shape here does not refer to a line in a proper sense,but refers to a rectangle or an oblong with a large aspect ratio. Forexample, the linear shape refers to a rectangle or an oblong with anaspect ratio of 2 or more (preferably from 10 to 10000). Accordingly,productivity can be improved by identifying a width of a beam spot ofthe laser light with that of a minor axis of the driver ICs.

In FIGS. 19A and 19B and FIGS. 20A and 20B, a mode in which the scanningline driver circuit is integrally formed with the pixel portion and thedriver ICs are mounted as a signal line driver circuit is shown.However, this embodiment mode is not limited to this mode, and thedriver ICs may be mounted as both a scanning line driver circuit and asignal line driver circuit. In that case, it is preferable todifferentiate a specification of the driver ICs to be used between thescanning line and signal line side. For example, a withstand pressure ofaround 30 V is required for the transistor composing the scanning linedriver ICs; however, a drive frequency is 100 kHz or less and a highspeed operation is comparatively not required. Therefore, it ispreferable to set a sufficiently long channel-length (L) of thetransistor composing the scanning line driver. On the other hand, awithstand pressure of around 12 V is enough for the transistor of thesignal line driver ICs; however, a drive frequency is around 65 MHz at 3V and a high speed operation is required; Therefore, it is preferable toset a channel-length or the like of the transistor composing a driverwith a micron rule.

In the pixel portion 1002, the signal line and the scanning line areintersected to form a matrix and a transistor is arranged in accordancewith each intersection. A TFT having a structure in which a channel isformed from an amorphous semiconductor or a semi-amorphous semiconductorcan be used as the transistor arranged in the pixel portion 1002 in thisembodiment mode. An amorphous semiconductor is formed by a method suchas a plasma CVD method or a sputtering method. It is possible to form asemi-amorphous semiconductor at a temperature of 300° C. or less withplasma CVD. A film thickness necessary to form a transistor is formed ina short time even in the case of a non-alkaline glass substrate of anexternal size of, for example, 550 mm×650 mm. The feature of such amanufacturing technique is effective in manufacturing a display deviceof a large-sized screen. In addition, a semi-amorphous TFT can obtainelectron field-effect mobility of 1 cm²/V·sec to 15 cm²/V·sec bycomposing a channel formation region with an SAS. Therefore, this TFTcan be used as a switching element of pixels and as an element whichcomposes the scanning line driver circuit.

As mentioned above, the driver circuit can be incorporated into an ELdisplay panel. According to this embodiment mode, a display device canbe easily manufactured even by using a glass substrate after fivegenerations, one side of which exceeds 1000 mm.

Embodiment Mode 7

A structure of a pixel applicable to display devices shown in EmbodimentMode 1 to Embodiment Mode 6 is explained with reference to equivalentcircuit diagrams shown in FIGS. 21A to 21F.

In a pixel shown in FIG. 21A, a signal line 410 and power supply lines411 to 413 are arranged in a column direction and a scanning line 414 isarranged in a row direction. In addition, a switching TFT 401, a drivingTFT 403, a current control TFT 404, a capacitor element 402, and alight-emitting element 405 are included.

A pixel shown in FIG. 21C has the same structure as the pixel shown inFIG. 21A except that a gate electrode of the driving TFT 403 isconnected to a power supply line 416 arranged in a row direction. Thedifference between the pixels shown in FIG. 21A and FIG. 21C is that thepower supply lines are formed from different conductive layer when thepower supply line 412 is arranged in a row direction (FIG. 21A) and whenthe power supply line 412 is arranged in a column direction (FIG. 21C).Here, a wiring connected to the gate electrode of the driving TFT 403 isfocused and the figures are separately shown in FIGS. 21A and 21C toshow that the wiring has different layers to be formed.

In the pixels shown in FIG. 21A and FIG. 21C, the driving TFT 403 andthe current control TFT 404 are connected in series. It is preferable toset a channel length L3 and a channel width W3 of the driving TFT 403and a channel length L4 and a channel width W4 of the current controlTFT 404 so as to satisfy L3/W3: L4/W4=5 to 6000:1. As an example of thecase satisfying 6000:1, it is when L3 is 500 μm, W3 is 3 μm, L4 is 3 μm,and W4 is 100 μm.

The driving TFT 403 operates in a saturation region and controls acurrent value flowed through the light-emitting element 405. The currentcontrol TFT 404 operates in a linear region and controls supply ofcurrent to the light-emitting device 405. It is preferable in terms ofmanufacturing steps if these TFTs have the same conductive type. Inaddition, not only an enhancement type but also a depletion type TFT maybe used for the driving TFT 403. In the present invention having theabove-mentioned embodiment, the current control TFT 404 operates in alinear region; therefore, a slight variation of VGS in the currentcontrol TFT 404 does not affect a current value of the light-emittingelement 405. In other words, the current value of the light-emittingelement 405 depends on the driving TFT 403 operated in a saturationregion. In the invention having the above-mentioned embodiment, adisplay device in which image quality is improved by improving luminancevariation resulted from variations in TFT properties can be provided.

FIG. 21A and FIG. 21C each show a structure in which the capacitorelement 402 is provided; however, the invention is not limited thereto.When a gate capacitor or the like can be substituted for a capacitorthat can hold a video signal, explicitly, the capacitor element 402 maynot be provided.

The light-emitting element 405 has a structure in which anelectroluminescent layer is sandwiched between two electrodes, andpotential difference between a pixel electrode and an opposite electrode(between an anode and a cathode) are provided so that a voltage in aforward bias direction is applied. The electroluminescent layer iscomposed of widespread material such as an organic material or aninorganic material, and fluorescence when luminescence returns from asinglet excited state to a ground state and phosphorescence whenluminescence returns from a triplet excited state to a ground state areincluded in luminescence of this electroluminescent layer.

A pixel shown in FIG. 21B has the same structure as the pixel shown inFIG. 21A except that a TFT 406 and a scanning line 415 are added. In thesame manner, a pixel shown in FIG. 21D is the same as the pixelstructure shown in FIG. 21C except that a TFT 406 and a scanning line417 are added. In the TFT 406, ON or OFF is controlled by the scanningline 415 that is newly arranged. When the TFT 406 is turned ON, anelectric charge held in the capacitor element 402 is discharged, and theTFT 406 is turned OFF. In other words, it is possible to forcefully makea state in which current does not flow through the light-emittingelement 405 by disposing the TFT 406.

Therefore, in the structures of FIG. 21B and FIG. 21D, a lighting periodcan be started simultaneously with or right after a start of a writingperiod without waiting for writing of a signal in all pixels.Accordingly, it is possible to improve a duty ratio.

In pixels shown in FIGS. 21A to 21D, the TFT 401 controls input of avideo signal to a pixel. When the switching TFT 401 is turned ON and thevideo signal is inputted to a pixel, the video signal is held in thecapacitor element 402. A plurality of TFTs connected in series to thelight-emitting element 405 is provided like pixels shown in FIGS. 21A to21D, and one of them is operated in a saturation region; therefore,display that controls variation of luminance in light-emitting element405 can be carried out.

In a pixel shown in FIG. 21E, a signal line 410 and power supply lines411 and 412 are arranged in a column direction, and a scanning line 414is arranged in a row direction. In addition, a switching TFT 401, adriving TFT 403, a capacitor element 402, and a light-emitting element405 are included. A pixel shown in FIG. 21F has the same structure as apixel shown in FIG. 21E except that a TFT 406 and a scanning line 415are added. When display is carried out with time gray scale, a rate of alight-emitting period to a non-light emitting period can be increased bydisposing the TFT 406 also in a structure of FIG. 21F.

Embodiment Mode 8

In a display device shown in Embodiment Mode 1 and Embodiment Mode 2,one mode in which a protective diode is provided for a scanning lineinput terminal portion and a signal line input terminal portion isexplained with reference to FIG. 15. A switching TFT 231 and a drivingTFT 232 are provided for a pixel 102 in FIG. 15.

Protective diodes 561 and 562 are provided for the signal line inputterminal portion. These protective diodes are manufactured in the samestep as that of the switching TFT 231 and the driving TFT 232. Theprotective diodes 561 and 562 are operated as a diode by being connectedto a gate and one of a drain and a source. FIG. 16 shows an equivalentcircuit diagram such as a top view shown in FIG. 15.

The protective diode 561 includes a gate electrode 550, a semiconductorlayer 551, an insulating layer for channel protection 552, and a wiring553. The protective diode 562 has the same structure. Common potentiallines 554 and 555 connecting to this protective diode are formed in thesame layer as that of the gate electrode. Therefore, it is necessary toform a contact hole in a gate insulating layer to electrically connectto the wiring 553.

A mask may be formed by a droplet discharge method and an etchingprocess may be carried out to form a contact hole in the gate insulatinglayer. In this case, when an etching process by atmospheric pressuredischarge is applied, a local discharge process is also possible, and itdoes not need to form a mask over an entire surface of a substrate.

A signal wiring 238 is formed in the same layer as that of a wiring 220in the switching TFT 231 and has a structure in which the signal wiring238 connected thereto is connected to a source side or a drain side.

Protective diodes 563 and 564 of the input terminal portion of thescanning signal line side also have the same structure. According to thepresent invention, the protective diodes provided in an input stage canbe formed at the same time. Note that the position of depositing aprotective diode is not limited to this embodiment mode and can be alsoprovided between a driver circuit and a pixel as shown in FIG. 3.

Embodiment Mode 9

FIGS. 27 and 28 shows an example of constituting an EL display module byusing a TFT substrate 200 manufactured by a droplet discharge method. InFIGS. 27 and 28, the TFT substrate 200 is provided with a pixel portion101 including a pixel 102.

In FIG. 27, the same TFT as that formed in a pixel or a protectivecircuit portion 701 operating in the same manner as a diode by beingconnected to a gate and one of a source or a drain of the TFT isprovided between a driver circuit 703 and the pixel 102 and outside thepixel portion 101. A driver IC formed from a single crystalsemiconductor, a stick driver IC formed from a polycrystallinesemiconductor film over a glass substrate, a driver circuit formed froman SAS, or the like is applied to the driver circuit 703.

The TFT substrate 200 is fixed to a sealing substrate 236 by sandwichinga spacer 708 formed with a droplet discharge method therebetween. Evenwhen the substrate has thin thickness or an area of the pixel portion isenlarged, the spacer is preferable to be provided to hold constant aspace between the two substrates. A light-transmitting resin materialmay be filled to solidify or anhydrous nitrogen or an inert gas may befilled in a gap between the TFT substrate 200 and the sealing substrate236 over a light-emitting device 234.

FIG. 27 shows the case where the light-emitting element has a structureof a top emission type, and light is radiated in a direction of an arrowshown in the drawing in the structure. Each pixel can carry outmulticolor display by differentiating a light-emitting color by using apixel 102 a for red, a pixel 102 b for green, and a pixel 102 c forblue. At this time, color purity of the luminescence emitted outside canbe improved by forming a colored layer 709 a, a colored layer 709 b, anda colored layer 709 c corresponding to each color on the side of thesealing substrate 236. In addition, as the white light-emitting element,the pixels 102 a, 102 b, and 102 c may be combined with the coloredlayers 709 a, 709 b, and 709 c.

An external circuit 705 is connected to a scanning line or signal lineconnection terminal provided on one end of the TFT substrate 200 with awiring board 704. In addition, a heat pipe 706 and a heat sink 707 maybe provided to be in contact with the TFT substrate 200 or in vicinitythereof to have a structure in which a heat dissipation effect isimproved.

FIG. 27 shows a top emission type EL module; however, a bottom emissionstructure may be acceptable by changing a disposition of a structure ofthe light-emitting element or the external circuit substrate.

FIG. 28 shows an example in which a resin film 709 is attached by usinga sealant 235 and an adherent resin 702 on the side where a pixelportion is formed over a TFT substrate 200 to form a sealing structure.A gas barrier film preventing permeation of water vapor may be providedon the surface of the resin film 709. FIG. 28 shows a structure ofbottom emission in which light of a light-emitting element is radiatedthrough a substrate; however, a top emission structure is alsoacceptable by giving light-transmitting properties to the resin film 708or the adherent resin 702. In either case, much more thin and lighterdisplay device can be obtained by applying a film sealing structure.

Embodiment Mode 10

An EL television receiver can be completed by an EL display modulemanufactured by Embodiment Mode 9. FIG. 29 shows a block diagram of amain structure of the EL television receiver. As a structure shown inFIG. 1, there is the case where a scanning line driver circuit 903 and asignal line driver circuit 902 are mounted by a TAB method by forming apixel portion 901. As a structure shown in FIG. 2, the scanning linedriver circuit 903 and the signal line driver circuit 902 are mounted onthe pixel portion 901 and a periphery thereof by a COG method. As shownin FIG. 3, there is the case where a TFT is formed from an SAS, and thesignal line driver circuit 902 is separately mounted as a driver IC byintegrally forming the pixel portion 901 and the scanning line drivercircuit 903 over a substrate. However, any one of modes may be applied.

As another structure of an external circuit, in an input side of a videosignal, a signal received from a tuner 904 includes a video signalamplifier circuit 905 that amplifies a video signal; a video signalprocessing circuit 906 that converts signal outputted therefrom into acolor signal corresponding to each color of red, green, and blue; acontrol circuit 907 for converting the video signal into an inputspecification of a driver IC; or the like. The control circuit 907outputs a signal into the scanning line side and the signal line side,respectively. In the case of digital driving, a signal division circuit908 is provided on the signal line side and may have a structure inwhich an input digital signal is provided by dividing into m-pieces.

In a signal received from the tuner 904, an audio signal is transmittedto an audio signal amplifier circuit 909, and the output thereof isprovided for a speaker 913 through an audio signal processing circuit910. A control circuit 911 receives control information of a receivingstation (a receiving frequency) or sound volume from an input portion912 and transmits a signal to the tuner 904 or the audio signalprocessing circuit 910.

As shown in FIG. 30, the television receiver can be completed byincorporating the EL module illustrated in FIGS. 27 and 28 into a casing920 by incorporating such an external circuit. A display screen 921 isformed by the EL display module, and a speaker 922, operation switches924, and the like are provided as other attached equipment. Accordingly,the television receiver can be completed according to the presentinvention.

Of course, the invention is not limited to the television receiver andis applicable to a display medium with a large-sized area such as aninformation display board at a station, an airport, or the like, or anadvertisement display board on the street as well as a monitor of apersonal computer.

1. A light-emitting device comprising: a light-emitting element in whicha light-emitting material is sandwiched between a pair of electrodes ina pixel; and a thin film transistor including, from a substrate side, alamination of: a base layer; a gate electrode formed by fusingconductive nanoparticles over the base layer; a gate insulating layerformed in contact with the gate electrode, the gate insulating layerincluding at least a layer comprising a silicon nitride or a siliconnitride oxide, and a layer comprising a silicon oxide; and asemiconductor layer, wherein the base layer is formed from a metalmaterial and the base layer not overlapping with the gate electrode isoxidized, and wherein the light-emitting element and the thin filmtransistor are connected in the pixel.
 2. A light-emitting devicecomprising: a light-emitting element in which a light-emitting materialis sandwiched between a pair of electrodes in a pixel; and a thin filmtransistor including, from a substrate side, a lamination of: a baselayer; a gate electrode formed by fusing conductive nanoparticles overthe base layer; a gate insulating layer formed in contact with the gateelectrode, the gate insulating layer including at least a layercomprising a silicon nitride or a silicon nitride oxide, and a layercomprising a silicon oxide; a semiconductor layer; wirings connected toa source and a drain and formed by fusing conductive nanoparticles; anda silicon nitride layer or silicon nitride oxide layer formed by beingin contact with the wirings, wherein the base layer is formed from ametal material and the base layer not overlapping with the gateelectrode is oxidized, and wherein the light-emitting element and thethin film transistor are connected in the pixel.
 3. A light-emittingdevice comprising: a light-emitting element in which a light-emittingmaterial is sandwiched between a pair of electrodes in a pixel; a firstthin film transistor including, from a substrate side, a lamination of:a base layer; a gate electrode formed by fusing conductive nanoparticlesover the base layer; a gate insulating layer formed in contact with thegate electrode, the gate insulating layer including at least a layercomprising a silicon nitride or a silicon nitride oxide, and a layercomprising a silicon oxide; and a semiconductor layer; a driver circuitincluding a second thin film transistor formed by having the same layerstructure as that of the first thin film transistor; and a wiringextended from the driver circuit and connecting to the gate electrode ofthe first thin film transistor, wherein the base layer is formed from ametal material and the base layer not overlapping with the dateelectrode is oxidized, and wherein the light-emitting element and thethin film transistor are connected in the pixel.
 4. A light-emittingdevice comprising: a light-emitting element in which a light-emittingmaterial is sandwiched between a pair of electrodes in a pixel; a firstthin film transistor including, from a substrate side, a lamination of:a base layer; a gate electrode formed by fusing conductive nanoparticlesover the base layer; a gate insulating layer formed in contact with thegate electrode, the gate insulating layer including at least a layercomprising a silicon nitride or a silicon nitride oxide, and a layercomprising a silicon oxide; a semiconductor layer; wirings connected toa source and a drain and formed by fusing conductive nanoparticles; anda silicon nitride layer or silicon nitride oxide layer formed to be incontact with the wirings; a driver circuit including a second thin filmtransistor formed by having the same layer structure as that of thefirst thin film transistor; and a wiring extended from the drivercircuit and connecting to the gate electrode of the first thin filmtransistor, wherein the base layer is formed from a metal material andthe base layer not overlapping with the gate electrode is oxidized, andwherein the light-emitting element and the thin film transistor areconnected in the pixel.
 5. The light-emitting device according to anyone of claims 1 to 4, wherein the conductive nanoparticles comprisesilver.
 6. The light-emitting device according to claim 2 or 4, whereinthe semiconductor layer contains hydrogen and halogen and is asemi-amorphous semiconductor having a crystal structure.
 7. Thelight-emitting device according to claim 2 or 4, wherein the drivercircuit is composed only of an n-channel type thin film transistor. 8.The light-emitting device according to any one of claims 1 to 4, whereinthe thin film transistor includes the semiconductor layer containinghydrogen and halogen and which is a semiconductor having a crystalstructure, wherein the thin film transistor is capable of being operatedin electric field effect mobility of from 1 cm²/V·sec to 15 cm²/V·seccm².
 9. The light-emitting device according to any one of claims 1 to 4,wherein the light-emitting device is a display screen.